DBS Surgery Basics for Parkinson's Disease

Treatments for PD: Deep Brain Stimulation

We already know that not all PD patients are eligible for Deep Brain Stimulation and that it appears to be effective for some but not all of the people who do receive the treatment. DBS is used in some advanced stages of PD that do not respond well to meds in order to reduce tremors and involuntary movement. It is used in younger and older patients alike. According to CNN, more that 35,000 people have undergone the procedure worldwide. According to one study when successful, DBS a 71% showed an increase in "on" time to about 4.6 hours. In that study about 40% of the patients demonstrated some adverse affects.

Deep brain stimulation (DBS) is a surgical procedure which consists of implanting high frequency electrodes in the subthalmic nucleus (movement center) in order to stimulate neurons to produce brain-derived neurotrophic factor (BDNF) through an implanted pacemaker-like device. Essentially the surgery when successful interrupts the faulty signals of dopamine cell loss. It targets the subthalmic nucleus, thalmus or globus pallidus as predetermined through an MRI or CT. The result is that many Parkinson's patients who receive the treatment find that they require less medication for the PD symptoms they have. The PD treatment is given unilaterally to many patients, bilaterally to others. Some opt for one side only to determine who it will work for them.

The complicated procedure is not without its negative side effects in some cases. There have been neuro-cognitive changes even when there is improvement in motor function. Depression, falls, gait disturbance, motor dysfunction, dystonia, balance and cardiac issues are also side effects in some patients. Sometimes there are infections at the pacemaker site which is usually in the chest. These symptoms may depend upon where the electrodes are placed. If Optogenics is developed to the point of state of the art for PD and use in DBS, we will certainly see far more precision in the placement of the electrodes.

The procedure itself occurs under local anesthetic so that the patient can be awake. The patient's head is immobilized in a frame and an MRI is done to pinpoint where the electrode is to be implanted. Two incisions are made in the skull and the microelectrode is passed into the brain. Current is passed through the electrode and increased while the patients responds to questions and performs certain movement tasks. After trial and error, the correct location is determined and the permanent electrode is placed and secured. The hospital stay is usually a few days.

After the swelling has subsided usually about a week later, the neurostimulator wires are connected to the electrodes. The pacemaker is placed usually in the chest. It may be another two to four weeks before it is turned on. In theory the patients can control the current flow through the pacemaker which is usually implanted in the patient's chest. In actuality the patient meets with the neurologist several times for stimulator adjustment.

The stimulation can be adjusted or turned off unlike the thalamotomy which Michael J Fox underwent seven years after his diagnosis, DBS is reversible in that it can be turned off or adjusted as in cases where tremors recur. When sucessful, the results of DBS can be a radical and remarkable change.

DBS is being used as an alternative therapy to thalamotony and pallidotomy which are permanent irreversible surgical procedures, It is used for control of PD tremor and control of essential tremor. It is being investigated for primary dystonia (involuntary muscle contractions) as well as for intractable epilepsy, cluster headaches which are usually vascular and associated with high blood pressure, chronic intractable pain, morbid obesity and obsessive-compulsive behavior (OCD)

One thng that is important to remember if you are considering Deep Brain Surgery is the Neurosurgical Team that will be performing the surgery. Don't be afraid to ask those questions about their experience and track record. Patients need to be proactive about their treatments.

DBS is not an inexpensive surgery. Costs can vary from $50,000 to $120,000 although in many cases are covered by Medicare and private insurance. Nonetheless, the co-pay can be very high.

In most clinical trials, patients with atypical symptoms, surgical contraindications such as MRIs or past PD surgery are excluded. Most studies will take both genders up to 75 or 80 years of age. What is necessary is that patients must fully disclose their medical history which includes psychiatric history; a desire for the surgery without full disclosure can lead to unexpected side effects.

So who does DBS work for or rather why does it work? How are the cells calmed or stimulated by the electrical shocks they receive? That still isn't clear but researchers in Scotland are exploring the idea that by stimulating other areas perhaps they can affect postural symptoms and gait issues also. One thing that is known is that when successful, DBS can improve the quality of life for the recipient.

Addendum:
On April of 2009, 50 DBS experts assembled to share experiences with Deep Brain Surgery procedures. They reached a consensus, per a recent news release issued by the UCLA Los Angeles Newsroom on October 10, 2010.

The findings include the best candidates for DBS; the importance of having an experienced team with an expertise in stereotactic neurosurgery performing the surgery. For some patients, DBS can be used for patients who have had PD surgeries. It is important to remember that certain treatments of the subthalmic nuclei can increase depression. And a reminder that surgery has complications with infection ranking highest.

You can read the full news release at the UCLA website.

References:
The first link is for DBS clinical trials - both closed and recruiting.
VIDEOS about DBS
You can watch video clips for PPN, dystonia and tremor.
And have your choice of many clips at YouTube.
If you live in Norway, there is a DBS clinical trial currently recruiting:
Clinical trial BCT00855621
Contact: Dr Mathias Toft 4799514189
Open to: 18-75 years
Gender: both
To study motor function, quality of life and cognitive function
Who is a good candidate for Deep Brain Stimulation
The medical history of DBS

Coming next:
Spinal Cord Stimulation
Optogenics
Magnetic Stimulation